1. Field of the Invention
The present invention relates to a camera system, more specifically relates to a camera system wherein functions of the camera are increased by attaching to a camera body an accessory such as an IC card performing a functional control of the camera body.
2. Description of the Prior Art
Recently, IC cards having the predetermined function are suggested to be attached to a camera body to increase the function of the camera. In the case of the IC card for an exposure program among such IC cards, it has the exposure program of which contents differ from those of an exposure program stored in the camera body.
Conventionally, where the IC card having such a function is attached to the camera body, considering that a photographer intends to prefer the contents of the IC card, the function of the IC card is designed to take precedence over that of the camera.
However, in photographing by using this IC card for the exposure program, there are some cases where other functions set on the camera body such as a forced ON of electric flashlight, and a focal length of a lens are unsuitable for the exposure program of the IC card regarding the photographing scene and the aim in photographing. This occurs, for example, in the case where the exposure programming is performed on the assumption that a subject at a bright and comparatively far palce is photographed as similar to a program card for outdoor sports and athletic meeting. Accordingly, in such cases, it is desirable that the exposure program of the IC card is changed-over to that of the camera body.
While, as a prior art, it is disclosed in the Japanese Laid-Open Patent Publication No. 78033/1982 that an appropriate program mode is selected by a selecting member from among a plurality of program modes without IC cards. Similarly, the Japanese Laid-Open Patent Publication No. 198031/1983 discloses selection of a program mode by a selecting member from among a plurality of program modes and further discloses that the controlled diaphragm aperture value and the controlled shutter speed of the selected program mode can be replaced with those of another program mode when they are not suitable for the aim in photographing. And, the Japanese Laid-Open Patent Publication No. 198032/1983 discloses that warning by means of a pictorial symbol is displayed in such cases. It is not proposed that the functions of the camera are increased and changed-over by preparing a plurality of such IC cards.
However, there are some cases where the functions of the IC card is undesirable to be used depending on photographing circumstances. As an example, there is the case where a snapshot (a meeting photograph) is taken after a moving subject is photographed by using the IC card constituted as the program card for sports. It is, however, very troublesome to perform the removing operation of the IC card from the camera body after considering whether use of the IC card is suitable or not on all such occasions.
Moreover, in all the above-mentioned prior arts, there is no disclosure regarding the change-over of the exposure program between the camera body and the accessory such as an IC card.